This invention relates to electromagnetic waveguides and, more particularly, to a waveguide having a strip dielectric structure.
In recent years, applications have been developed for the use of millimeter and submillimeter wave frequencies for the transmission of information. Conventional metal waveguides become quite lossy and difficult to fabricate as the wavelengths involved become shorter. As a result, alternatives to conventional microstrip techniques have been investigated. One suggested alternate technique for millimeter wave integrated circuits is the employment of so-called dielectric waveguide structures such as image guides and silicon waveguides. However, in these structures the waveguide boundaries are generally required to be extremely mechanically smooth so as to avoid radiation loss. To minimize losses due to surface roughness, costly technological processes are needed. Also, in the case of an image guide, conductor losses in the ground plane can be substantial due to the strength of the field near the conductor.
The conductor loss in microstrip lines is relatively large because the field is strong at the edges of the microstrip. In typical dielectric rod waveguides, there are no losses to the ground plane since there is none, but the absence of a ground plane can lead to inconvenience regarding heat sinking or application of a DC bias.
It is an object of the present invention to provide a waveguide which is responsive to the problems of the prior art as set forth.